Fire resistant polymers produced by reacting phenyl isothiocyanate and tris (hydroxymethyl) phosphine

ABSTRACT

Methylol phosphines, methylol phosphines in combination with amine or amido compounds or water soluble adducts of these methylol phosphines and amides or amines when mixed and reacted with mono, di or polyisocyanates wherein the isocyanate groups are attached to carbon atoms are particularly valuable for the preparation of thermosetting flame resistant polymers. The polymers which are produced are crosslinked phosphorus and nitrogen containing polymers in which the reoccurring structure units each contain a phosphorus atom, that is a component of the radical tris(methylene)-phosphine (-CH2)3P and is linked to at least one isocyanate radical by connecting urethane structure. The polymer forming solutions are also valuable for the preparation of flame-, glow-, wrinkle- and shrink-resistant textiles, said textiles being produced by impregnating fabrics with these solutions and causing reaction and polymer formation by application of heat.

United States Patent [191 Beninate et al.

[ 1 July 29, 1975 1541 FIRE RESISTANT POLYMERS PRODUCED BY REACTING PI-IENY L ISOTHIOCYANATE AND TRIS (HYDROXYMETIIYL) PHOSPI-IINE {75] Inventors: John V. Beninate, Gretna; Donald J.

Daigle, New Orleans; George L. Drake, Jr., Metairie; Wilson A. Reeves, Metairie; Darrell J. Donaldson, Metairie, all of La.

[73] Assignee: The United States of America as represented by the Secretary of Agriculture, Washington, DC.

[22] Filed: May 31, I972 [21] Appl. No.: 258,165

Related US. Application Data [62] Division of Ser. No. 141,352, May 7, 1971, Pat. No.

[52] U.S.Cl....260/77.5 AQ; 106/15 FP; 117/138.8F; ll7/l38.8 N; 117/141; 117/142; 117/143 A; 117/155; 260/775 AR [51] Int. Cl C08g 22/16 [58] Field of Search 260/775 AR, 77.5 AQ

[56] References Cited FOREIGN PATENTS OR APPLICATIONS 743,644 9/1966 Canada 260/775 AR Primary Examiner-M. .1. Welsh D. Hensley [57] ABSTRACT Methylol phosphines, methylol phosphines in combination with amine or amido compounds or water soluble adducts of these methylol phosphines and amides or amines when mixed and reacted with mono, di or polyisocyanates wherein the isocyanate groups are attached to carbon atoms are particularly valuable for the preparation of thermosetting flame resistant polymers. The polymers which are produced are crosslinked phosphorus and nitrogen containing polymers in which the reoccurring structure units each contain a phosphorus atom, that is a component of the radical tris(rnethylene)-phosphine (Cl-l P and is linked to at least one isocyanate radical by connecting urethane structure.

The polymer forming solutions are also valuable for the preparation of flame-, g1ow-, wrinkleand shrink-resistant textiles, said textiles being produced by impregnating fabrics with these solutions and causing reaction and polymer formation by application of heat.

1 Claim, No Drawings 1 FIRE RESISTANT POLYMERS PRODUCED BY REACTING PHENYL ISOTHIOCYANATE-AND TRIS (HYDROXYMETHYL) PHOSPHINE A non-exclusive, irrevocable,"royalty-freelicense in the invention herein described," throughout the world for all purposes 'of the United States Government, with the pdwer'to grant s'ublice'nses'fo'r such purposes, is hereby granted to the Gov ernment of the United-States of America; e

This is'a division of application Ser. No.-"l4l,35'2, filed May 7,l 97l',-and n'ow U.S.'*P'at.' No. 3,697,316.

This invention relates to new phosphorus and nitrogen containing polymers,'processe's' for their production,an'd processes of employing these polymers in the flameproofing of certain organic fibrous material or mixture of various-fibers. f

In general; this in'ventionrelat'es to polymers capable of being produced by the reaction of a methylol phosphine compound of the formula where P is trivalent, R is a l-iOCH H alkyl, aryl or alicyclic group with a monomeric nitrogen compound which contains one, two, orthree isocyanateor isothiocyanate radicals; and to processes of reducing the combustibility of fibrous organic materials. The preferable methylol phosphine for use in thisinvention is the one whereinR is a CH OH group. When R is a -C.H QH group ,the compound is a white crystalline solid M.P. 58C and is soluble in. water, alcohol, and other solvents. For purposes of the reaction, each isocyanate group can be considered difunctional as shown in the equationbelow. l f

where R can be alkyl, aryl or alicyclic.

We have discovered that tris(hydroxyrnethyl)phosphine (hereinafter referred to by this'same name or as TI-lP) in the presence or absence of HCl-lO reacts with monomeric aliphatic, aromatic, and cyclic compounds containing at least one isocyanate radical, to produce polymers. The polymers which are produced are crosslinked phosphorus-and nitrogen containing polymers in which the reoccurring structureunitseach contain a phosphorus atom; that is a component-of the radical tris(methylene)phosphine [(-'CH P] and is linked to at least one isocyanate radical by the connecting urethane structureu 1 We have also discovered'that compounds which contain at least one isocyanate radical attached to a carbon atom react with adductsof methylol phosphine (e.g. compounds that contain at least two HOCl-I groups attached to a trivalent phosphorus atom) and compounds such as melamine, methylolmelamines, cyanamide, urea, thiourea and the like, and by heating form thermosetting polymers which are flame, rot-. and mildew-resistant. a a

The soluble. methylol phosphine adducts are preparfedby reacting tris(hydroxymethyl)phosphine either in the presence or absence of free formaldehyde with an essentially monomeric amide or amine in a suitable solvent. lnforder to'make-thesoluble and useful adducts of this invention there must be an excess of methylolph'osphorus radicals (--P CH OH) in the adduct. For purposes of the reaction -tris(hydroxymethyl)- phosphine is trifunctional, the functionality of the amine or amideis determined bythe number of hydrogen or methylol radicals attached to trivalent nitrogen in the compound to be reacted with.tris(hydroxyme-- thyl)phosphite. .Thus the adduct contains unreacted methylol phosphorus radicals; The adducts are essentially materials which. contain the structure: (HOCH2),,,P-(CH2N)H. where m and n are intergers of 1 or- 2 and'thesum of m+n is 3. Polymers provided by this invention can be produced under acidic, neutral. andalkaline conditions.

Such polymers can be produced in 'theform of. liquid or solid synthetic resins. Such resins can be deposited on the surfaces and/or in the interstices of hydrophilic fibrous organic materials, i.e., organic materials which absorbor adsorb water on most of their surface area. When such organic fiber materials are treated with suchresins,the-combustibility of the-hydrophilic fibrous organic-materialyis reduced and the treatment resists removal by laundering, drycleaning, and like chemical-treatments. Such resins can also be deposited on the surface of n onhydrophilic materials to form flame-resistant coatings In the case of; mixed hydrophilic and hydrophobic; fibers the resin can be'deposited in and on the surface of'thefibers. The resin treatments provide valuable new products. Suitable isocya nates which can be. used in this inventionyhavethe typi cal structures RNCO or OCNRNCO where R =,.H, alkyl, or aryl alkyl substituted alkyl or aryl. groups. In :the case of the aliphatic isocyanates such as hexamethylene diisocyanate, the reaction produces valuable new urethane.polymers the exhibit in a rather widely variable but controlled degree the properties of athermosetting noncombustable polymer. The new polymers contain the phosphorus and: nitrogen groups described above.

In the case.of monomeric aliphatic compounds containingat-least-one isocyanate radical such as cyclohexadiisocyanate, the reaction produces valuable new flame resistant polymers incorporating aliphatic rings and the above described phosphorusnand this invention can be .formed by reacting the phosphorus compound or the phosphorus compound adducts with a mixture of isocyanate compounds.

I-lydrophilic fibrous organic materials are rendered flame resistant by impregnating the material with dimethylformamide (DMF) solutions of, or. homogeneous dipersions of the respective monomers and thereafter curing the impregnated material. Hexamethylenediisocyanate (HMDl) and toluene diisocyanate (TDl) are preferred members of the isocyanate compounds; and tris(hydroxymethyl)phosphine, its amine or its with the higher temperatures.

. The mixed flame retardant polymer provided .by this inventioncan be used in the treatmentpf organic fibrous textile materials such as cotton, flax, linen,

amido adducts are preferred members of the phospho- 5 r yon. fl nylon an the like. as well as blends of rus compounds. these material. Chemically modified fibers such as cya- The polymers provided by this invention can be prom hyl rboxymethylated and am inoethylated duced in the form of hard brittle polymers, soft rubbery C IIO and the like; regenerated CeiiUlOSiC til s polymers, or semihard polymers'These polymers can such as the viscose rayoris; or proteinaceous textiles as be'molded by the conventional techniques of molding l0 silk, wool, and the like can also be treated with these thermosetting resins. These polymers are valuable maflame retardant polymers. The textile materials can be terials for use in the production of molded synthetic treated in the form of slivers, yarns or fabrics. Polymers plastic articles, such as buttons, food containers, eleccontained in the mixedflame retardants can be sepatrical insulators, paints, varnishes, protective coatings rately formed or can be produced in situ in the textile for paper and textiles, and the like; all, having a reby the reaction of the materials with which the textile duced flammability. i is impregnated. The mixtures can be used as the only Condensation polymers of tris(hydroxymethyl)phosmaterials with which the textile is impregnated or used phine or the amine or amido adduct with the isocyanate in conjunction with other textile flameproofing, creaseor isothiocyanates are preferably prepared by agitating proofing, wrinkleproofing, and the-like textile treating a mixture of the phosphorus compounds and the isocyresins or agents; or in conjunction with textile lubrianate compound in DMF while heating until polymercants, water repellents, and the like textile treating ization occurs. The preferred relative amounts of phosagents. In the treatment of textiles interfacial polymerphorus and nitrogen compounds used to polymerize iZatiOn is a p ibili y. can be calculated by conventional methods used for Where a textile iS ng impregnated, it is of advanondensation polymerization b assuming h 1 2'5 tage to remove the excess impregnating liquid by passtris(hydroxymethyl)phosphine is trifunctional, (2) one g the teXtiie through Squeeze adjusted to PP methylol group of the phosphorus compound con- 3 p t y y high pressure Prior to 'y denses with one of the isocyanates or isothiocyanate and Curing the impregnated teXtiieit is also of advah radicals-attached to a carbon atom of the isocyanate g to y the textile at a temperature of about from compound. 3' 85 to about 180C for about from 1 minute to about Each isocyanate group can be considered difunc- 6 minutesi i tional. For example, one and a half moles of the isocya- Aithotigh cataiysts are not necessary to make nate can react with one mole of the tris(hydroxyme- Vehtioh work of the Cataiyst Systems used in the thyl)phosphine. The preferred ratio of three tenths to Preparation of diii'abie l fabrics such as g zi three moles of the diisocyanate compound per mole of Zh(NO3)2 the amihe hy and the iike eah tris(hydroxymethyl)phosphine. be used i Phenyl isothiocyanate is employed in a ratio with The degree of flamepi'ootihg pa to a textile y tris(hydroxymethyl)phosphine of about f to these phosphorus and nitrogen resins can be varied about from a low degree to a very high degree by varying the "Tris(hydroxymethyl)phosphine and the amine or 40 amount of P y P in the fabricamido adducts are of themselves capable of polymerizsome f e of 'f p g teXtiieS in accoring They also win copolymerize with materials (e'gh dance with this invention are as follows: Textiles diisocyahates) over an extreme wide range For exam treated by this process are flame resistant, glow resisple trace quantities of tris(hydroxymethyl) phosphihe tant, rotand mildew-resistant; the effects of the treatadded to essentially 100% solution of HMDl will copoment are perm'fmenti i resistant to laundering, y lymerize with HMDI to produce a new phosphorus and cleaning, alkal and acid treatments. The polymers nitrogen containing resin. The new nitrogen and phosthemselves t mmmescem h expcfsed to the t phorus polymers are formed um the quantity of l The following examples are illustrations of the inventris(hydroxymethyl)phosphine is used up in the formation: tion of the polymer.

Polymerization reactions conducted in accordance EXAMPLE 1 with the process of this invention can be carried to the Various organic fibrous materials were impregnated extent of producing solid, liquid, or gel-like polymers. with solutions containing THP and aliphatic and aro- Partial polymers can be isolated, completingthe polymatic diisocyanate and isocyanate compounds, dried merization or partially polymerized thermosetting for 1-3 minutes at to C, and cured for 3-10 monomers. minutes at to C. All of the treated fabrics with When using phenyl isothiocyanate and tris(hydroxthe exception of the nylon, formed a black carbonaymethyl)phosphine, polymerization is effected at a ceous char when exposed to flame, indicating the prestemperature of from 28Cl55C for a period of time 60 ence of phosphorus. The type of material treated, soluranging about from 24 hours to about 3 minutes, the tion composition, dry and cure conditions, and properlonger periods of time being used in conjunction with ties of the treated materials are contained in the followthe lower temperatures and the shorter periods of-time ing tab e. 1 I

Drying Cure Conditions Conditions Match- Type of Organic Fibrous Soln. Temp. Time Temp. Time t Angle Material Treated Used* C Min. C Min. Test Hand Strength Color Cotton twill fabric A 85 3 v 155 3 I80 Crisp Fair White Polyester/gotten blend fabric A 85 3 120 l0 I80 Crisp Good White Wool fabric A 85 3 120 l() 180 Crisp Fair No change Contmued: i

Drying Cure i 1;, Conditions Conditions Match Material'Treated i "Used* C 'Min. C ,Minl. :J est Hand Strength Color Paper A i 85 '3 120 170 Good Good White Strip leather A 85 3 155 ,4 160 No Chg No change No change Cotton twill fabric 8 85 3 155 3 90 Crisp Good White Polyester/cotton blend fabric B 85 3 155 3 90 Fair Good White Wool fabric B 85 3 155 3 180 Crisp Good No change Paper B 85 3 155 3 120 Good Good White Leather B 85 3 155 3 180 No chg No change No change Nylon B 85 3 155 3 Fair Good White Cotton twill fabric C 105 l 155 3 90 Crisp Good White Polyester/cotton blend fabric C 105 l 155 3 90 Crisp Good White Wool C 105 l 155 3 180 Fair Fair No change Paper C 105 l 155 3 135 Good Good White Leather C 105 1 155 3 180 No chg No change No change Cotton twill fabric D 105 l 155 4 90 Fair Good White Wool D 105 1 155 4 180 Fair Good No Change Pa er D l 05 l 155 4 90 Good Good White Nylon jD 105 l 155 4 Good Good White Polyester/cotton blend fabric D 105 l 155 4 90 Good Good White Cotton twill fabric E 85 2 155 3 160 Crisp Good White Polyester/cotton blend fabric E 85 2 155 3 160 Crisp Good White Description of solutions used: A parts THP, 15 parts toluene diisocyanate. 70 parts dimethylformamide (DMF). B 7.5 parts THP. 7.5 parts toluene diisocyanate. 85 parts dimethylformamide. C 15 parts THP 15 parts phenyl isocyanate. 70 parts dimethylformamide, D 7.5 parts THP, 7.5 parts phenyl isocyanate, 85 parts di emthylformamide. E 15 parts THP. l5 parts hexamethylene diisocyanate, 70 parts dimethylformamide. "Nylon sample resisted burning and melted with the formation of black carbonaceous char containing phosphorus,

EXAMPLE 2 EXAMPLE 4 Match Type of Organic Fibrous Soln. Angle Material Treated Used* Test Strength Cotton twill fabric A 160 Good Polyester/cotton blend fabric A 160 Good Cotton twill fabric B 160 Fair Polyester/cotton blend fabric B 90 Good Cotton twill fabric C 135 Good Polyester/cotton blend fabric C 135 Good Description of solutions used:

A THP-cyanamide adduct [62 parts THP, 21 parts cyanamide 18 parts formalin, 90 parts H O, heated for 10 min.]-, 40 parts of adduct mixed with 5 parts hexumethylene diisocyanate, and 15 parts DMF.

B Tl-lP-cyanamide adduct [62 parts THP, 21 parts cyanamide (50%). 18 parts formalin. 90 parts H O, heated for 10 min.]; 40 parts of adduct mixed with 5 parts toluene diisocyanate and 15 parts DMF.

C THP-cyanamide adduct [62 parts THP, 21 parts cyannmide (50%), 18 parts formalin, 90 parts H O, heated for 10 min.]-, 40 parts of adduct mixed with 5 parts phenyl isocyanate and 15 parts DMF.

EXAMPLE 3 A solution containing 15 parts THP, 15 parts toluene diisocyanate, and 70 parts DMF was steam heated to evaporate the solvent, then heated in oven at 155C for 30 minutes which resulted in the formation of clear, pale yellow, hard polymer which resisted burning when exposed to flame and formed a black char. Polymer was insoluble in water and ethanol.

A solution containing 15 parts THP, 15 parts phenyl isocyanate, and '70 parts DMF was steam heated to evaporate the solvent, then heated in oven at 155C for 30 minutes which resulted in the formation of clear, pale yellow, hard polymer which resisted burning when exposed to flame and formed a black char. Polymer was insoluble in water and ethanol.

EXAMPLE 5 A THP-cyanamide adduct was produced by heating for 10 minutes a solution containing 62 parts THP, 21 parts of 50% cyanamide, 18 parts formalin, and parts H O. Forty parts of this adduct was mixed with 5 parts of hexamethylenediisocyanate, and 15 parts of DMF. The solvent was evaporated from the solution by heating with steam, then the mixture was heated in an oven at C for 30 min. to form a clear, pale yellow, hard polymer which resisted burning when exposed to flame, and formed a black char. Polymer was insoluble in water and ethanol.

EXAMPLE 6 Forty parts of the THP-cyanamide adduct which was prepared as shown in Example 5, was mixed with 5 parts of toluene diisocyanate and 15 parts DMF. The solution was steam heated to evaporate the solvent thenheated in an oven at 155C for 30 minutes to form a yellow, brittle, porous polymer which resisted burning when exposed to flame and formed a black char. Polymer was insoluble in water and ethanol.

EXAMPLE 7 Forty parts of the THP-cyanamide adduct which was preparedas shown in Example 5, was mixed with 5 parts of phenyl isocyanate, and 15 parts DMF. The solution was steam heated to evaporate the solvent then heated in an oven at 155C for 30 minutes to form a clear, pale yellow, hard polymer which resisted burning 8 about from 28 to about C for periods ranging about from 24 hours to about 3 minutes, the longer periods of time being used in conjunction with the lower temperatures and the shorter periods of time with the higher temperatures. 

1. THE POLYMERS PRODUCED BY MIXING PHENYL ISOCYANATE AND TRIS(HYDROXYMETHYL)PHOSPHINE IN SOLUTION WITH DIMETHYLFORMAMIDE IN MOLE RATIOS OF ABOUT FROM 1:3 TO ABOUT 3:1 AND POLYMERIZING AT TEMPERATURES ABOUT FROM 28* TO ABOUT 155*C FOR PERIODS RANGING ABOUT FROM 24 HOURS TO ABOUT 3 MINUTES, THE LONGER PERIODS OF TIME BEING USED IN CONJUCTION WITH THE LOWER TEMPERATURES AND THE SHORTER PERIODS OF TIME WITH THE HIGHER TEMPERATURES. 